The art is exemplified by U.S. Pat. No. 3,248,796; 3,318,005; 4,344,428; 4,389,885; 4,481,714; 4,646,752 and U.S. Pat. No. 4,905,698.
Various medical procedures exist whereby a long flexible tube is advanced into a body orifice (e.g., the esophagus or the colon) so that images, either video or ultrasound, can be transmitted to the observer. Once the tube is inserted into the orifice, it is often difficult to judge distance properly. Recently, the medical profession is requiring more and more precise measurements of endoscopic and ultrasonographic procedures for either the staging of pathological lesions or research protocols.
The present invention provides an apparatus which will measure the precise distance a probe has been inserted into an orifice, and transmit that data to a recording instrument or other associated devices. The invention is not limited to medical procedures, and can be used in a host of other applications.